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  1. #101
    Ice Hole's Avatar
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    Quote Originally Posted by Matt Phillips View Post
    Thanks for taking the time to go through all of this :)

    Not sure what you're asking. The graph I posted is for the 35 brick break, not a tower collapse. Can you be more precise about what sort of "aerodynamic downforce" you are refering to?
    Ok I was confused about the graphs. Let me start over with something more basic.

    I may be missing posts or confused (no sarcasm intended) but your OP said this:

    Quote Originally Posted by Matt Phillips View Post
    This has implication for 9/11 research of any variety, because the official "Pancake Collapse" theory of the WTC collapse events would be constrained in the same way as the multi brick breaks above (ie: constrained to a constant rate of collapse). I am still digging for good measurememnts of what was actually observed, but I don't believe the towers actually fell at a constant rate. It seems they accelerated.
    )
    But NIST's 2005 updated report said this after the original FEMA pancake theory was successfully challenged and after additional steel testing had completed by NIST, wasn't the entire pancake theory tossed out (for good reason), after additional peer review NIST performed alongside private sector engineers?

    Based on this comprehensive investigation, NIST concluded that the WTC towers collapsed because: (1) the impact of the planes severed and damaged support columns, dislodged fireproofing insulation coating the steel floor trusses and steel columns, and widely dispersed jet fuel over multiple floors; and (2) the subsequent unusually large jet-fuel ignited multi-floor fires (which reached temperatures as high as 1,000 degrees Celsius) significantly weakened the floors and columns with dislodged fireproofing to the point where floors sagged and pulled inward on the perimeter columns. This led to the inward bowing of the perimeter columns and failure of the south face of WTC 1 and the east face of WTC 2, initiating the collapse of each of the towers. Both photographic and video evidence—as well as accounts from the New York Police Department aviation unit during a half-hour period prior to collapse—support this sequence for each tower.

    NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel “trusses” integrated with a concrete slab; see diagram below). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.
    Last edited by Ice Hole; 11/29/2010 5:50pm at .

  2. #102
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    While the NIST crimping-in model is not THE pancake model, it is still A pancake model, and the analogy still holds for the new model. Now what's all this about aerodynamics? :)
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  3. #103
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    Quote Originally Posted by Matt Phillips View Post
    While the NIST crimping-in model is not THE pancake model, it is still A pancake model, and the analogy still holds for the new model. Now what's all this about aerodynamics? :)
    From my read of your OP, you are trying to square up why accelerations would be seen at all, as opposed to constant rate of "flattening" similar to the brick breaking videos. It seems like your graph data actually shows that small accelerations/decelerations are visible in the brick videos after all.

    I used pitch analysis software to determine the location (in time) of each impact, and measured the difference between impact peaks in ms.
    I was wondering if the Bernoulli effect explains what you are seeing (since I'm almost positive it's what you're recording via audio). Let's call it Accordion theory, vs pancake theory.

    You are recording sound waves formed by air being forced from between the bricks and eventually into a microphone, so you are relying on the Bernoulli effect to gather your data. Likewise I think it might well explain the same accelerations/decelerations you are seeing.

    I've seen a lot of discussion contributions about terminal velocity, gravity, intertia but not a lot of air/fluid dynamics which seems to be an important component of the brick model and especially the collapse of the towers.

    Air-resistant stacks of almost anything: bricks, floors, parachutes or pancakes are all going to exhibit experiencepositive and negativelift forces between each other when rapidly compressed.

    Each brick has a pocket of air between it and the one above it, and as each pocket above is "popped", the brick experiences a tiny amount of lift due to the sudden decreased air pressure above it (and thus a small amount of acceleration upwards), quickly followed by the "pop" below it, causing decreased air pressure below the brick and a small increase in drag/downforce.

    Those same forces are seen blowing air/dust out from between the bricks as they break, and maybe that is a good visual to help you see my idea. The same forces blowing dust towards the camera are also at work on each individual brick, in both vertical directions (each brick receives a tiny tiny bit of lift upwards as the air above is forced out, but then experiences an increased drag downward the breaking brick forces the air below it.

    What do you think?

  4. #104
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    Quote Originally Posted by W. Rabbit View Post
    From my read of your OP, you are trying to square up why accelerations would be seen at all, as opposed to constant rate of "flattening" similar to the brick breaking videos. It seems like your graph data actually shows that small accelerations/decelerations are visible in the brick videos after all.
    Yes, it's small but it's there.


    I was wondering if the Bernoulli effect explains what you are seeing (since I'm almost positive it's what you're recording via audio). Let's call it Accordion theory, vs pancake theory.
    Try clapping your hands, but stop just short of actually making palm to palm contact. Do it as hard has you can withou actually letting your palms touch. Hear anything? What I'm tracking in the graph is the high frequency "ping" of brick smacking brick.

    You are recording sound waves formed by air being forced from between the bricks and eventually into a microphone, so you are relying on the Bernoulli effect to gather your data. Likewise I think it might well explain the same accelerations/decelerations you are seeing.
    Try the clap-without-contact experiment from above, but do it an ince or so away from your ear. That low frequency wum wum is the sound you are describing, not the clicl-clicl-click of the brick stack breaking.

    I've seen a lot of discussion contributions about terminal velocity, gravity, intertia but not a lot of air/fluid dynamics which seems to be an important component of the brick model and especially the collapse of the towers.
    Really the take home message from this thread is that the brick stack break-front accelerates much slower than the 9.8 m/s/s of a brick in free fall (which means energy is being expended to do work beyond just making things go faster). In the case of the towers, it seems very little energy is expended to do extra work, as the breakfront really does accelerate at close to 9.8 m/s/s. This is a problem for the official model, because the closer the rate of fall is to uninterrrupted freefall, the smaller the amount of energy available to move things around/bust stuff up is. It would seem most of the energy in the brick-break system is used up, you know, breaking the bricks, and only a small amount remains to create acceleration. In the case of the towers it seems only a tiny proportion of the energy available was expended breaking things up, which is really not what is described in either of the models taken up by the Govt over the years. Put another way, if the towers came down in the manner described in either the pancake, or "accordion" models, one would have expected to see a much longer collapse event, with significantly less acceleration. That was not observed, and so both models have very poor explanatory power.

    Air-resistant stacks of almost anything: bricks, floors, parachutes or pancakes are all going to exhibit experiencepositive and negativelift forces between each other when rapidly compressed.
    sure, and moving all that air around will be part of that "work" we discussed above, and that energy will be unavailable for acceleration. In other words this will tend to slow everything down.

    Each brick has a pocket of air between it and the one above it, and as each pocket above is "popped", the brick experiences a tiny amount of lift due to the sudden decreased air pressure above it (and thus a small amount of acceleration upwards), quickly followed by the "pop" below it, causing decreased air pressure below the brick and a small increase in drag/downforce.
    I'm not sure I like the way you are phrasing this but... OK.

    Those same forces are seen blowing air/dust out from between the bricks as they break, and maybe that is a good visual to help you see my idea. The same forces blowing dust towards the camera are also at work on each individual brick, in both vertical directions (each brick receives a tiny tiny bit of lift upwards as the air above is forced out, but then experiences an increased drag downward the breaking brick forces the air below it.

    What do you think?
    I think you just nailed part of why what you saw on TV on 9/11 can't have happened as described in the very short time we all observed actually being the case. All tinfoil hats aside, the models under consideration are completely inadequate.
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  5. #105
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    Quote Originally Posted by Matt Phillips View Post
    Put another way, if the towers came down in the manner described in either the pancake, or "accordion" models, one would have expected to see a much longer collapse event, with significantly less acceleration. That was not observed, and so both models have very poor explanatory power.
    Ok I get what you are saying now. I've never believed that the official NIST reports were 100% on the ball, I definitely concur that short of blowing up some buildings, the models are entirely artificial (but for now, the "best" we have to go up against crazy conspiracy theories).

    Quote Originally Posted by Matt Phillips View Post
    I think you just nailed part of why what you saw on TV on 9/11 can't have happened as described in the very short time we all observed actually being the case. All tinfoil hats aside, the models under consideration are completely inadequate.
    I started thinking about Bernoulli/air/fluid model a while ago when I read about the "tube within a tube" architecture of the WTC and wondered how it might have formed a sort of "spud gun" that basically shot what was all at the top of the towers down through the interior/perimeter tubes towards the ground, essentially using just thrust and gravity.

    Hear me out, I know it sounds nuts and is just my own pet theory.

    When you think about it a 110-story skyscraper with the WTC's tubular architecture is like a big rifle barrel pointed at the ground. At the top of the tower you have this enormous amount of potential energy. Then you have these paired, pressurized tubes (aha Bernoulli) and inside the tube, structure and air.

    Planes hit the towers, fireproofing is removed, columns shattered, fires burn, etc, causing enough structural instability until eventually...

    Suddenly, remaining supports give way and right off the bat, you get a top-to-bottom buckling of the entire structure, causing a pressure wave from close to the altitude where the planes hit towards the more stable portions of the tower (towards earth). The pressure wave causes an accordion-like Bernoulli effect (not on the floors per say, but on the air between them), where even a minor amount of the air between floors is forced out of the "tube", leaving this enormous low pressure system inside the interior "tube" of the building, directly underneath that huge amount of PE, and creating a real big problem.

    Sp you have this enormous amount of PE at the top of the tower, sitting on top of a massive tube or straw with such low air pressure inside it, and now gravity takes over....the contents on the top may actually experienced some thrust through the tube and towards the earth, in addition to gravity. So freefall acceleration still explains the speed of the fall here, but there may be some pneumatic effect going on as well.
    Last edited by Ice Hole; 11/30/2010 3:13pm at .

  6. #106
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    Ok I may be missing something here after reading through all of this but it sounds like your working from the assumption that the towers fell at free fall speed. I am under the impression that they did not.
    Here is a web page that talks about this in depth.
    http://www.debunking911.com/freefall.htm

  7. #107
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    Quote Originally Posted by goodlun View Post
    Ok I may be missing something here after reading through all of this but it sounds like your working from the assumption that the towers fell at free fall speed. I am under the impression that they did not.
    Here is a web page that talks about this in depth.
    http://www.debunking911.com/freefall.htm
    I think you're confusing velocity (speed) and acceleration (rate of change in speed). When Matt says "free fall" in his OP and followups he means free fall acceleration. The longer something is falling, the faster it is moving (up to the terminal velocity), at a standard rate (in the Earth's atmosphere) of 9.81 meters per second per second. At t=0s your velocity=0, at t=1s your velocity is 9.8m/s, t=2s and you're now at 19.6 m/s, etc, assuming no other forces (like lift or thrust).

    Something I noted in http://www.debunking911.com/freefall.htm

    Italian debunker shows us more than 16 seconds to collapse. That's almost twice free fall speed from the 110th floor.
    According to that statement, a 110th floor jumper would take well more than 16 seconds to hit the ground at free fall. Dr. Greening's report uses seismographs (like Matt used audio) to try to calculate the timing of the collapses to try to model why the towers fell as quickly as they did. In the case of both towers, some other NATURAL force is at work. In Dr. Greening's paper he models this as momentum/energy transfer (kind of like Matt's dominos/bricks), in my wild theory some sort of aerodynamic pull due to low pressure might have contributed. NIST's models seem to avoid the issue and say it was all gravity combined with a failed support structure...which now seems to be a bit of a underwhelming "best effort" attempt now that I look at it in this light.

    On the other hand it's nice to see academics like Matt and Dr. Greening going above and beyond to more closely examine the science, prompted of course as a reaction to the sheer volume of disinformative bullshit being spread by truthers.

    Nonetheless the data obtained over the first four seconds are quite sufficient to show that WTC 2 fell significantly faster than WTC 1. What is more, the measured downward movement of each Tower may be compared with our calculated values for the same downward movements. The results of such a comparison are shown in Figure 1. This figure uses calculations with E1 set to 0.8 GJ. This value of E1 was selected to include 0.2 GJ of collapse energy to crush the concrete floors. The total collapse times were then calculated as follows: WTC 1: tc = 13.48 s ; WTC 2: tc = 12.07 s
    So....like Matt's experiment (I think) points out, there is definitely some real evidence that there was some other (natural) forces at work that helped speed the collapses that are not really part of the "official" findings or models, making them ultimately weak and exploitable. Whether the forces involved are aerodynamic, fluid, or some truly bizarre dynamic of energy transfer....I will be the first to say I just don't know.
    Last edited by Ice Hole; 11/30/2010 4:45pm at .

  8. #108
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    ^^^ is a fair enough representation of what I argued that I wont quibble over details. Except for "(natural)"... there is no reason to weigh in on that one way or another. My primary concern is over whether the Gubmint analysts did their job, and my conclusion is that, like everyone else in that gubmint, they likely did not.
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